X-Git-Url: https://git.rohieb.name/openwrt.git/blobdiff_plain/6e7905d2a36799482b283ad8e3f0f9fa520f09ac..d4aeb1b5c81c3adfa2db01e9a6eebf9ec5b6d35b:/target/linux/brcm63xx-2.6/files/arch/mips/bcm963xx/time.c

diff --git a/target/linux/brcm63xx-2.6/files/arch/mips/bcm963xx/time.c b/target/linux/brcm63xx-2.6/files/arch/mips/bcm963xx/time.c
new file mode 100644
index 000000000..b615c2842
--- /dev/null
+++ b/target/linux/brcm63xx-2.6/files/arch/mips/bcm963xx/time.c
@@ -0,0 +1,114 @@
+/*
+<:copyright-gpl
+ Copyright 2004 Broadcom Corp. All Rights Reserved.
+
+ This program is free software; you can distribute it and/or modify it
+ under the terms of the GNU General Public License (Version 2) as
+ published by the Free Software Foundation.
+
+ This program is distributed in the hope it will be useful, but WITHOUT
+ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ for more details.
+
+ You should have received a copy of the GNU General Public License along
+ with this program; if not, write to the Free Software Foundation, Inc.,
+ 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
+:>
+*/
+/*
+ * Setup time for Broadcom 963xx MIPS boards
+ */
+
+#include <linux/autoconf.h>
+#include <linux/init.h>
+#include <linux/kernel_stat.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/time.h>
+#include <linux/timex.h>
+
+#include <asm/mipsregs.h>
+#include <asm/ptrace.h>
+#include <asm/div64.h>
+#include <asm/time.h>
+
+#include <bcm_map_part.h>
+#include <bcm_intr.h>
+
+static unsigned long r4k_offset;	/* Amount to increment compare reg each time */
+static unsigned long r4k_cur;		/* What counter should be at next timer irq */
+
+/*  *********************************************************************
+    *  calculateCpuSpeed()
+    *      Calculate the BCM6348 CPU speed by reading the PLL strap register
+    *      and applying the following formula:
+    *      cpu_clk = (.25 * 64MHz freq) * (N1 + 1) * (N2 + 2) / (M1_CPU + 1)
+    *  Input parameters:
+    *      none
+    *  Return value:
+    *      none
+    ********************************************************************* */
+
+static inline unsigned long __init calculateCpuSpeed(void)
+{
+    UINT32 pllStrap = PERF->PllStrap;
+    int n1 = (pllStrap & PLL_N1_MASK) >> PLL_N1_SHFT;
+    int n2 = (pllStrap & PLL_N2_MASK) >> PLL_N2_SHFT;
+    int m1cpu = (pllStrap & PLL_M1_CPU_MASK) >> PLL_M1_CPU_SHFT;
+
+	return (16 * (n1 + 1) * (n2 + 2) / (m1cpu + 1)) * 1000000;
+}
+
+
+static inline unsigned long __init cal_r4koff(void)
+{   
+	mips_hpt_frequency = calculateCpuSpeed() / 2;
+	return (mips_hpt_frequency / HZ);
+}
+
+
+/*
+ * There are a lot of conceptually broken versions of the MIPS timer interrupt
+ * handler floating around.  This one is rather different, but the algorithm
+ * is provably more robust.
+ */
+irqreturn_t brcm_timer_interrupt(struct pt_regs *regs)
+{
+	int irq = MIPS_TIMER_INT;
+
+	irq_enter();
+	kstat_this_cpu.irqs[irq]++;
+
+	timer_interrupt(irq, regs);
+	irq_exit();
+	return IRQ_HANDLED;
+}
+
+
+void __init brcm_time_init(void)
+{
+	unsigned int est_freq, flags;
+	local_irq_save(flags);
+
+	printk("calculating r4koff... ");
+	r4k_offset = cal_r4koff();
+	printk("%08lx(%d)\n", r4k_offset, (int)r4k_offset);
+
+	est_freq = 2 * r4k_offset * HZ;
+	est_freq += 5000;   /* round */
+	est_freq -= est_freq % 10000;
+	printk("CPU frequency %d.%02d MHz\n", est_freq / 1000000,
+		   (est_freq % 1000000) * 100 / 1000000);
+	local_irq_restore(flags);
+}
+
+
+void __init plat_timer_setup(struct irqaction *irq)
+{
+	r4k_cur = (read_c0_count() + r4k_offset);
+	write_c0_compare(r4k_cur);
+	set_c0_status(IE_IRQ5);
+}